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Full text of "The "Bassalian Fauna;" "Pentacrinus asteriscus""

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September 12, 1884.] 



SCIENCE. 



223 



Mr. Pourtales' first dredgings, were written under 
very considerable difficulties, as 1 well remember 
hearing from the author himself. But the ' priority 
in scientific research,' which Mr. Rathbun claims for 
Pourtales' work, had been accorded to it four years 
previously, at the earliest possible opportunity, in 
the Proceedings of the Royal society. So far as I 
know, this honor has never been 'denied' to one 
who would have been the last to claim it for himself. 
I fully admit, however, that the date of his earlier 
work has been incorrectly given in certain popular 
accounts of the subject; but this was done acci- 
dentally, and without the slightest intention of 
appropriating any credit for the work of British 
naturalists which was justly due elsewhere, as will 
be evident from what I have said already. 

P. Herbert Carpenter. 
Eton college, "Windsor, Eng., 
Aug. 11. 



The ' bassaliau fauna ; ' 
asteriscus.' 



Pentacrinus 



I notice that Mr. Gill has " recently proposed the 
name 'bassalian realm' for the collective deep-sea 
faunas." I do not know whether it is proposed to 
define this name more strictly by assigning to it any 
particular bathymetrical limits ; but it may be well to 
notice, that, in his presidential address to the biologi- 
cal section of the British association at Plymouth in 
1877, Mr. Gwyn Jeffreys suggested the use of the 
name "'benthal' (from the Homeric word pevdog, 
signifying the depths of the sea) for depths of one 
thousand fathoms and more," while retaining the 
term ' abyssal ' for depths down to one thousand 
fathoms. 

There is another point to which I have long thought 
of directing the attention of the readers of Science, 
and I therefore take this opportunity of doing so. 

The surveys of Hay den, Wheeler, and others, in 
Utah, Idaho, and Wyoming, have revealed the very 
wide distribution, in beds of Jurassic age, of a cri- 
noid which has been called Pentacrinus asteriscus. 
Nothing is known of this form but a number of 
stem- joints (I speak under correction, and shall be 
pleased to hear that I am wrong); but most of the 
figures of these joints which I have seen (e.g., that 
given by White in the paleontology of Wheeler's sur- 
vey) seem to me to indicate that the type should be 
referred to Extracrinus rather than to Pentacrinus. 
The essential characters of the stem-joints of Extra- 
crinus are well shown in plate liii. of Buckland's 
' Geology and mineralogy,' figs. 9-13 ; on tab. 101 of 
Quenstedt's 'Encriniden,' especially figs. 24, 27, 33, 
and 37; and also on plate xii. of the Austins' ' Mono- 
graph of recent and fossil crinoids.' The five in- 
terradial petals are quite narrow, and much less 
distinctly oval than in Pentacrinus, sometimes be- 
coming almost linear, with rounded outer ends. The 
interpetaloid spaces are plain, and devoid of sculp- 
ture ; while the markings at the sides of the petals 
are much more delicate than in Pentacrinus, having 
more the character of striae or crenulation than of 
coarse ridges. They are also much more numerous 
than in Pentacrinus, and are limited to the sides of 
the petals, not reaching the outer edge of the joint- 
face. Under these circumstances, I suspect that it 
is to Extracrinus, and not to Pentacrinus, that we 
must refer the joints which were described by Meek 
and Hayden as having lance, oval, petaloid areas, 
"bounded by rather narrow, slightly elevated, trans- 
versely crenulate margins." 

Extracrinus was proposed by the Austins for the 
two well-known liassic fossils, Pentacrinus briareus 



and P. subangnlaris ; but recent investigations have 
shown that the genus extends up into the great 
oolite (Bathonien) of Britain, France, and Switzer- 
land. I have no knowledge, however, of any triassic 
species of Extracrinus; though Pentacrinus is well 
represented in the St. Cassian beds, and has been 
found associated with Encrinus in the 'wellenkalk' 
of Wiirtemberg. 

It is therefore interesting to find that the triassic 
form of Pentacrinus asteriscus, which was obtained 
by the fortieth parallel survey from the Dun Glen 
limestone and the Pah Ute range, differs from the 
Jurassic specimens found in south-east Idaho and 
western Wyoming, almost precisely in those points 
which distinguish Pentacrinus from Extracrinus. 
According to Hall and Whitfield, the chief distinc- 
tion of the triassic forms lies "in the more obtuse 
points of the star, and the filling-up of the angles 
between the points, and also in the broader form of 
the elliptical figures on the articulating surfaces of the 
disks." They suggest that the differences may pos- 
sibly be of specific value; but, having carefully 
studied a large variety of stem-joints of Penta- 
crinidae, both recent and fossil, I am inclined to go 
farther, and to suspect that the triassic type may be- 
long to Pentacrinus, but the Jurassic form to Extra- 
crinus. 

The two genera differ very considerably in the char- 
acters of the calyx and arms, as will be fully ex- 
plained in the report on the Pentacrinidae dredged 
by the Challenger and the Blake, which will appear 
in the course of the winter. But, in the mean time, I 
shall be most grateful for any information respecting 
Pentacrinus asteriscus, in addition to that which has 
been already made public; and I need not say that I 
should much like to have the opportunity of making 
a personal examination, both of the triassic and the 
Jurassic specimens. P. Herbert Oabpentee. 

Eton college, Windsor, Eng., 
Aug. 11. 

Points on lightning-rods. 

The following passage occurs in J. E. H. Gordon's 
excellent " Physical treatise on electricity and mag- 
netism," vol. i. p. 24: "It was held that the knobs 
[on the ends of ligbtning-rodsj must be most effica- 
cious, because the lightning was seen to strike them, 
and never struck the points. The fact that a point 
prevents the lightning from ever striking at all was 
not known." 

This is not true. The highest rod on my house is 
some fifteen feet above the others, and about thirty 
feet higher than the surrounding buildings; and yet, 
notwithstanding the fact that it is tipped with a 
brush of five points, it was struck a few years ago. 
The points are gilded iron, and the topmost one was 
melted into a ball about one-eighth of an inch in 
diameter. The rods are all connected by horizontal 
pieces held about three inches from the tin roof by 
glass insulators, after the fashion of ignorant light- 
ning-rod agents. The neighbors say that the sparks 
flew so thickly between the rods and the roof, as to 
resemble a sheet of flame. The shock was, singularly 
enough, so slight that it is doubtful whether it was 
due to the electrical discharge, or the deafening crash 
of thunder that instantly followed the splitting sound 
of the spark. A. B. Porter. 

Indianapolis, Aug. 23. 

Photographs of the interior of a coal-mine. 

One of the most interesting enterprises to which 
the preparations for the New Orleans exposition have